"Wire in tube", what's best to use for each?

Discussion in 'Metals' started by Keith M, Sep 27, 2020.

  1. Keith M

    Keith M Staff Member Moderator

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    As I intend using the "wire in tube" method for points operation on my forthcoming 0 gauge layout, albeit operated by Hattons point motors as opposed to manual operation, I was wondering what others have used for both tube (plastic or maybe brass?) and wire (piano wire or something else?).
    The maximum length of any 'wire in tube' is likely to only be around 550mm, most less than that, so no long lengths involved causing problems due to friction etc, as the layout width is only 600mm, idea being to site the actual motors at the outer edge of the layout, concealed by buildings/scenery. Using brass tube will make it simple to solder tabs to the tube for fixing to the baseboard, but it'll be more expensive, alternately using plastic (Evergreen?) tube with fixing tabs glued to the tube is likely to be cheaper, then as to wire, piano wire, or perhaps some of the stainless steel rod used by the radio controlled modellers? I've seen dismantled butt hinges used as guides for operating wires, and I know that Gormo uses straightened wire coat hangers, but I was thinking of something as small a diameter in both tube and wire as possible to help concealment. All ideas/suggestions welcomed.
    Keith.
     
  2. ianvolvo46

    ianvolvo46 Staff Member Moderator

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    i used hollow knitting needles Keith .. they're cheap, come in various diameters and have a handle already fitted .. the smaller one is a snug fit inside the other

    [​IMG]

    [​IMG]
     
    Last edited: Sep 27, 2020
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  3. Jim Freight

    Jim Freight Full Member

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    I model in 4mm scale but this may also be feasible in 7mm.

    Mostly I use GEM wire in their PTFE tube operated by slider switches (operating wire attached through a hole in the switch slider toggle) or via point motors on some pointwork where motors were retrofitted due to a change of operators position.

    My railway is built on plywood boards with an overlay of 3mm closed cell foam and I run the tube between the two.

    To hold the PTFE tube in place at the switch/point motor, on longer and curved runs and near the point, I lightly apply staples with a staple gun so the tube is just held and apply a blob of hot melt glue, the combination of staple and glue keep the tube in place. As you probably know the slippery surface inherent to PTFE is difficult to bond to, however this works well for me.

    I used brass tube where the wire flew across air gap from frame to baseboard.

    If you use GEM wire keep it dry, it is low grade regarding rust, even damp lichen can rust it and water/detergent mix from ballasting can wick into the tube and a week or two later the wire rusts and jams solid in the tube, I had to rewire some 20 points, now I only dry ballast around the point end of the tube.

    Jim
     
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  4. gormo

    gormo Staff Member Administrator

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    G`day Keith,
    I will be using galvanized wire this time around. It`s the type used for fixing wire fencing and comes in various thicknesses. It`s available in rolls of approx. 50 meters from your hardware.
    I think mine is 0.8mm.....lost the label......it`s very cheap if you can find a size that will work for you....example below
    https://www.bunnings.com.au/whites-0-90mm-x-75m-galvanised-tie-wire-wirepak_p3064940
    I think if you have dead straight runs you will have no issues, as long as the wire is a nice fit in the tube. If it`s a sloppy fit, the wire can arc slightly and cause friction within the tube.
    A sloppy fit and arcing also increases the movement required to throw the point, so if you are working with say a slide switch, to dictate the movement, it may not have enough travel built in.
    The wire needs to be dead straight, but you know how to do that.
    I will be using PVC coated wire, which is that stretchy white cable that`s used for hanging curtains, as a tube.
    https://www.bunnings.com.au/windoware-5m-hooks-and-eyes-expanding-curtain-wire-kit_p1283497
    The Gal wire is a nice fit inside it and it can be secured with 4mm cable clips, however it may be a bit on the heavy side for your project.?
    :tophat:Gormo
     
  5. Gary

    Gary Wants more time for modelling.... Staff Member Administrator

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    I have used remote control areal tube and piano wire for my OO layouts...


    For my O gauge layout, I have used Evergreen Styrene tube and 1mm diameter welding wire. 1mm diameter piano wire could be used. As seen in the pics below, the diameter of the tube is approximately 3mm (1/8") and sits snugly into the groove I cut into the cork. This is held down with PVA, although an epoxy glue or Tarzans Grip would do the same job.

    Piano wire comes in 3' or 3'4" lengths and the Evergreen Styrene tube is approximately 340mm in length.

    On the edge of the baseboard I have used slide switches for point throw and polarity.



    Cheers, Gary.
     
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  6. jakesdad13

    jakesdad13 Staff Member Moderator

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    Hi Keith, it seems there are as many methods as members mate. I use small bore copper tube I get from a small place near Killamarsh just off the M1 jct 30. For the inner wire I use mig wire, I just had some in the shed.
    I will photograph the box with the copper tube, just for your information.

    Cheers, Pete.
     
  7. Keith M

    Keith M Staff Member Moderator

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    Thanks all. I have a Mig welder with a good supply of wire Pete, so that should take care of the inner, never gave that a thought, but I may as well use that rather than bother buying something else.:thumbup:
    Keith.
     
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